1. Field of the Invention
This invention relates to a ball joint and a method of manufacturing the ball joint used on joints in automotive steering mechanisms and suspension mechanisms.
2. Description of the Prior Art
Ball joints used on joints of automotive steering mechanisms and suspension mechanism are required to have a proper level of rigidity and be able to oscillate and swivel smoothly. To meet these requirements, the ball joints of a conventional type generally have the following construction, though it increases the manufacturing cost. A global head of a metal ball stud, which has a shank integrally formed therewith and projecting from the head, is slidably contained in a bearing seat made of hard synthetic resin. The bearing seat is pressed into a metal housing from a first opening at one end of the housing. The shank of the ball stud is allowed to project out of a second opening at the other end of the housing. A metal plug is caulked over the first opening of the housing to hold the bearing seat, together with the global head of the ball stud, in the housing. A rubber dust seal is mounted to cover an area between the other end of the housing and the shank of the ball stud. This dust seal is secured to the housing by a metal clip.
To lower the cost of the ball joints of this type, a construction as shown in FIG. 6 is currently employed. A global head 1a and a metal ball stud 1, which has a shank 1b integrally formed therewith and projecting from the head 1a, is slidably contained in a bearing seat 2 made of hard synthetic resin. This bearing seat 2 is pressed into a metal housing 3 from an opening 3a at one end of the housing 3. The shank 1a of the ball stud 1 is allowed to project out of a second opening 3b b at the other end of the housing 3. A thin engagement portion 3c provided outside the first opening 3a of the housing 3 is caulked over the bearing seat 2 to hold the bearing seat 2, together with the global head 1a of the ball stud 1, in the housing 3, without using a plug. A rubber dust seal 4 is used to cover the area between the other end of the housing 3 and the shank 1b of the ball stud 1. The dust seal 4 is secured to the housing by a metal clip 5.
In the conventional ball joint of FIG. 6, the plug is eliminated and the cost is reduced accordingly. However, the housing 3 still remains as complicated in structure as when a plug is used, and also requires a dome-shaped hollow portion 3d to be formed inside the housing 3 near the other end and the thin engagement portion 3c to be formed at one end of the housing. This requires cutting processes for manufacture.